Graphic: The anatomy of a tornado

This week a double tornado wrecked 300 homes in Pilger, Neb., killing two people. On Tuesday, a twister damaged 100 homes in Angus, Ont., about 100 kilometres north of Toronto. Tornadoes are random, chaotic, often deadly, and can take several forms, including satellite tornadoes and multi-vortex ones. How they are formed is still a bit of a mystery although there are several theories.